Description: 100% brand new and high quality Feature: Support multi-layer overlay to increase power and capacitance. Support subsequent expansion modules, support single-sided or double-sided battery. High current wiring, Full-chip high-current protection board and battery holder. High Conversion efficiency, Support multi-layer balanced release. With over-voltage protection function to prevent overshoot or over-discharge. With voltage equalization function, to ensure that multiple sets of voltage are the same, increase the life of the battery pack. Easy and simple to use and operate, no other tools needed to install. Installation: Install the battery according to the positive and negative sides on the circuit board. Be careful not to reverse it. Specifications: Item Type: Battery Holder Protection Board Material: plastic+metal+electronic components Size: 172x88mm/6.7x3.4in Color: As shown Optional Type: 1: Single-sided battery+standard version, 2: Single-sided battery+high advanced version, 3: Double-sided battery+standard version, 4: Double-sided battery+high advanced version, 5: 20A Protection Board, 6: 40A Protection Board, 7: 60A Protection Board Voltage: 29.4V(fully charged) Current: 20A, 40A, 60A Quantity: 1 PC Warm Tips:(Battery not included) 1.The 7S requires a 29.4v charger. 2.Do not use it on metal table top, pay attention to insulation and do not short circuit. 3.The charging current of each layer is not recommended to exceed 2a, otherwise the battery may generate heat (for example, if there is only one layer, choose 2a charger, and if there are two layers, choose 4a charger). 4.Look at the circuit board with the battery orientation,and all the batteries cannot be staggered in the same orientation. 5.Don't connect the power supply with the wrong positive and negative, there are signs on the circuit board, pay attention to observation. Note: Transition: 1cm=10mm=0.39inch Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Includes: 1 Set x Battery Holder Protection Board Kits (Not include the balance line shown in the picture)